国立情報学研究所 - ディジタル・シルクロード・プロジェクト
『東洋文庫所蔵』貴重書デジタルアーカイブ

182

THE OSCILLATIONS IN THE WATER-LEVEL OF THE LAKES.

In July 1865, Captain SMITH and Mr. HARRISON visited the lakes. Their narrative is very unreliable, but as they positively assert there was not the slightest trace of any stream or old water-course connecting the two lakes, it at least seems likely that the channel was then as dry as in Moorcroft's days.

On NAIN SING's map, 1866, there is no channel between the two lakes, but an effluence from the Rakas-tal to the Satlej, which is of course absurd, as the upper lake under all circumstances is the chief recipient of the water, which, if in sufficient quantity, lower down flows out from the Rakas-tai.

MONTGOMERIE's Pundits coming down from Western Tibet to the Manasarovar in 1868, made a map of the lake and found that no water flowed through the

channel.

KAWAGUCH1's statements cannot be used, but he has two interesting things to tell from his visit in August 1900. He was told by the Tibetans that the »Langchen Khanbab started from Lake Manasarovar». There was also said to be a connection between the two lakes every i oth or i 5th year. From his description as a whole one gets the impression that there was no water in the channel. It is of interest, however, that even the Tibetans pointed to the lowest order of periodicity, giving it an amplitude of i o to 15 years.

In December 1904 RYDER found the level of the Manasarovar only 2 feet below the threshold of the channel bed, and was told by the Tibetans, that every year during the rainy season there was a flow. As the surface, even so late as in December, stood so high as only 2 feet under the culmen of the bed, it seems almost certain that in September it must have been somewhat more than 2 feet higher that is to say, overflowing; so much the more as the Tibetans stated this to have been the case, meaning probably during the 2 or 3 last years before 1904.

Ryder also heard that the Satlej went out of the Rakas-tai before 1845. In 1904 there was no water in the bed until 6 miles from the lake, where marks and furrows in the bed proved flowing water from east to west. This may have been from the same springs which I saw three years later.

In 1905 SHERRING found the channel without water and the bed sanded up. He heard that no water had flowed through the channel since 1894, a tale that is not in harmony with Ryder's information. Sherring also heard of an underground outflow from the Rakas-tai. This belief is very common amongst the Tibetans, as I found, and very likely they may be right. The year 1905, was, as Sherring says, exceptionally dry.

In 1907 I found the channel dry and, of course, no outlet from the Rakas-tai. The surface of the Manasarovar was 13.45m. above that of the Rakas-tai, and 2.263m. below the highest point in the channel bed. Thus 1907 was a much drier year than 1904, when there was a difference of only 2 feet, even so late as in December.

In 1908 there was no effluence either from the lakes, but as that year was much richer in rain, the surfaces of the lakes must have been at a higher level.

NY